c#问题，求高手指教
系统提示，我的result=cmd.ExecuteReader();总是异常，一直出现对不起！数据查询失败！，但是连接好险没有问题的啊
下面是完整代码，就是写的一个登录验证程序
using System;
using System.Data.SqlClient;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Windows.Forms;

namespace supermarket_management_system
{
  public partial class Login : Form
  {
  public Login()
  {
  InitializeComponent();
  }
  string strcon = @"Data source=(local);Initial Catalog=supermarket management;Integrated Security=True";
  SqlConnection conn = new SqlConnection();
  SqlDataReader result;
  public bool confirm(string user, string password, string type)
  {
  conn.ConnectionString = strcon;
  string sql = "select * from USER where user_id='" + user + "'and user_password='" + password + "'and user_type='" + type + "'";
  SqlCommand cmd = new SqlCommand(sql,conn);
  cmd.Connection.Open();
  try
{
result = cmd.ExecuteReader();
}
catch (Exception)
{
MessageBox.Show("对不起！数据查询失败！", "提示");
}[color=#FF0000][/color] if (result != null)
  {
  if (result.Read())
  return true;
  result.Close();
  }  
  cmd.Connection.Close();
  return false;
  }
  private void button1_Click(object sender, EventArgs e)
  {
  int count=0;
  string user = textBox1.Text.Trim();
  string password = textBox2.Text.Trim();
  string type = null;
  if (radioButton1.Checked)
  type = "店长";
  else if (radioButton2.Checked)
  type = "保管员";
  else
  type = "收银员";
  if ((textBox1.Text != "") && (textBox2.Text != ""))
  if (confirm(user, password, type) == false)
  {
  if (count < 3)
  {
  count++;
  MessageBox.Show("用户登录失败！！！" + "你还有" + (3-count) + "次机会");
  }
  else
  this.Dispose();
  }

  }

  private void button2_Click(object sender, EventArgs e)
  {
  this.Close();
  }

  }
}


------解决方案--------------------
USER 是关键字加[],and前空格
string sql = "select * from [USER] where user_id='" + user + "' and user_password='" + password + "' and user_type='" + type + "'";

数据库名为supermarket management嘛？